The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method used for performing deposition on a semiconductor wafer by using Si source gas, for example.
In an epitaxial growth apparatus for Si, for example, H2 gas as carrier gas and SiH2Cl2 gas or SiHCl3 gas as source gas are used, and gas in which the aforementioned are mixed is supplied as process gas to a reaction chamber. Then, a wafer temperature is made to be about 1100° C., and Si is grown epitaxially on a wafer by a hydrogen reduction reaction.
At this occasion, reaction by-products such as polysilicon deposited on members such as a susceptor inside the reaction chamber are removed. Due to this, a cleaning (etching process) using Chlorine gas such as HCl gas is performed periodically. At this time, a Si—H—Cl polymer is generated as the by-product in the reaction chamber, is cooled near a ventilation outlet, and is deposited as oily silane (reactive polysiloxane).
The oily silane deposited as aforementioned is usually removed upon a periodically performed maintenance of the reaction chamber so as to prevent a ventilation system from being clogged. However, upon an air ventilation, there is a problem that H2 gas and HCl gas are generated by a surface reacting with water in the air.
Further, when the reaction chamber undergoes the air ventilation, although the oily silane has the surface reacting with the water in the air to generate H2 gas and HCl gas, the surface solidifies by turning into SiO2, and thereby further reaction can be suppressed. On a vertical surface, there is no problem because most of the deposited oily silane is solidified by turning into SiO2.
However, when a certain amount of the oily silane is collected on a horizontal surface, unreacted oily silane in a lower layer of a solidified portion reacts vigorously upon exfoliating the oily silane. Due to this, there is a risk of ignition and explosion of the H2 gas. This especially becomes a problem in a single wafer processing epitaxial growth apparatus, which frequency of the air ventilation is low and the oily silane is more likely to be collected.
Thus, considerations are given to removing the oily silane without performing the air ventilation either in a wet process or a dry process. However, since the reaction of the lower layer is suppressed in the oily silane when the surface thereof is oxidized, there is a need to repeatedly perform oxidation and surface removal, which is a problem which effects a throughput.